Washington (CNN) -- Activists with several free Gaza groups will symbolically surrender Thursday at a Congressman's office, after the lawmaker called for the prosecution of Americans who were aboard a flotilla raided last week by Israeli authorities.
On a conference call organized by the non-profit Israel Project last week, Rep. Brad Sherman, D-California, said that the Justice Department should prosecute any U.S. citizen aboard the well-publicized flotilla that was stopped by the Israeli military on its way to Gaza last week. Nine people were killed in the May 31 incident.
"So what is illegal is helping Hamas," Sherman said. "I will be asking the attorney general to prosecute all Americans involved in what was a clear effort to give items of value to a terrorist organization."
The U.S. State Department considers Hamas a foreign terrorist organization.
Sherman said the activists could be prosecuted under the Antiterrorism and Effective Death Penalty Act of 1996, which makes it illegal to give supplies to terror groups
Members of Gaza Freedom March said its group and others would offer themselves up for arrest Thursday at 2 p.m. ET.
"Should Rep. Sherman seek to arrest us, we have faith that no jury in America would possibly convict us for our humanitarian and human rights work in Palestine," the organizers said in a statement.
If Sherman does not have them arrested, the group said it will hold a memorial service for people who died in the raid.
The raid has sparked international condemnation and calls for an investigation.
Aid groups said they were trying to get supplies directly to those in Gaza that need it.
Israel said the ships violated their blockade of Gaza and that its troops were attacked with knives, metal poles and other objects when they boarded a ship.
Israel has said its naval blockade is in place to stop weaponry from reaching militants in Gaza intent on attacking Israel. But critics say the three-year blockade -- imposed after Hamas took over Gaza -- has deepened poverty in the Palestinian territory.
The U.N. Security Council has called for an inquiry into the flotilla raid, and the U.N. Human Rights Council has condemned the assault and voted to launch an investigation.